favre-bulle



M. P. E-BULLE.

ELECTRO AG ETIC CLO APPLICATION mm saw. 23, 1,41 1,243. Patented 1922.

1 s s -sn:n 1.

M. P. FAVRE-BULLE.

ELECTROMAGNETIC CLOCK. APPLICATION FILED SFT. 23. 1920.

1 ,41 1 ,243, Patented Mar. 28, 1922.

3 SHEETS-SHEET 2.

M. P. I-AVRE-BULLE.

ELECTROMAGNETIC CLOCK.

APPLICATION FILED SEPT. 23. I920. 1,41 1,243 Patented Mar. 28, 1922.

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE.

MAURICE PHILIPPE FAVRE-I BULLE, OF PARIS, FRANCE.

ELECTROMAGNETIC CLOCK.

Specification of Letters Patent. Patented Ian v28, 1922.

Application filed September 23, 1920. Serial No. 412,358.

clectro-magnetic: means and actuates and.

controls the movement 'of'the hands.

As is known, in clocks of the type under consideration the oscillations of the pendulum are kept up by the action of an intermittent current, passing through a coil, upon asystem of magnets, the magnets being fixed to the pendulum and the coil being stationary, or vice versa.

The clockwork mechanism according to the present invention permits of ensuring the transmission of the movement of the pendulum to the hands under the most favorable conditions and also of causing the periodic closure, atthe proper time, of the electric circuit feeding the coil which produces the electronagnetie force which keeps up the oscillations of the pendulum.

-It is characterized by special features which ensure perfect electrical and mechanical operation'by means of parts which are of very simple an(l='strong design and at the same time are extremely cheap to manu facture.

According to the invention, this mocha nism comprises an actuating pendulum, the oscillation of which is kept up by intermittent electro-magnetic action and the movement of the pendulum is transmitted to the hands by a driving arm, fixed to the pendulum, which rocks afork-shaped member pivoted at a fixed point and having a driving pawl pivoted thereon and acting upon a ratchet which actuates the minutehands through af suitable transmission. Furthermore, the said fork-shaped member, through contact of one of its prongs with the driving arm establishes the electric conncction which causes excitation of the coil actuating the pendulum, this excitation taking place in the neighborhood of the passage of the pendulum ast the head centre in one direction only, e ectric contact in the other direction being prevented by an insulating packing carried by the drivingarm or by the fork.

In order to facilitate understanding of the invention a form of execution of the mechanism fitted to a clock comprisin "fa pcmlulum'carrying a coil at its'extre'inity, is described below. This coil moves 'inthe neighborhood of a perrnanent inagnet' and periodically receives an impulse ow" to an electric current which passes throu "*it a t suitable intervals. But it is to be -cle a'rl'y, understood that this form of execution is only'given by way of example and thtcan other electric-magnetic system could-be used" comprising the application 'ojf the action-of a current upon a magnet (or upon another current or again upon a soft-iron armature) the only condition to be observed being that the effect of the passage of the current shall he to give rise to a force of suitable value which acts upon the pendulum in a direction: favourable to the upkeep of its oscillatory motion.

The clock in accordance with the inv'en tion is illustrated in the accompanying drawing, in which:

Figure 1 is a general-front view with portions in section along line 1 1 ofFig. ure 2- l Figure 2 is m section along line 22 of Figure 1. 'f'

'Figures 3, 4, 5 and 6 are principal parts of the clock.

Figure 6 is a front general view of a modification showin portions in section along line 11 of *igure 7.

Figure 7 is aside view with portions in section along line 2-2 of Figure 6.

Figure 8 is a plan view of this modified form.

Figure 9 is a detailed view of the fork shaped member according to this modification.

Figure 10 is a view of. thismember shown in section along line 5'-5 of Figure 9.

Figure 11 is also a sectional view along line 6-6 of Figure 9.

Referring first to Figures 1 to 6, the clock comprises a pendulum attached to the su ort 1 by a suitable suspension device a side view with portions etail views showing the method of operation of the.

.he bob of the pendulum is shown at 2 fixed to the extremity of the rod 3. This the end of the pendulum. A permanent magnet 5, of which only a portion is shown in the figure, is arranged in such a manner that one of its extremities penetrates into the coil and gives rise to an electromagnetic force acting in the direction of the arrow f when the coil is traversed by an electric current.

The actuation of the hands is cllccted by the pawl 6 acting upon the ratchet wheel 7 which is fixed to the worm 8.

This worm meshes with the toothed wheel 9 keyed on the shaft 10 of the minute hand 11.

The hour hand is actuated by an ordinary minute wheel-work.

The pawl 6 is pivoted at 13 on the furl:- shaped .member 14 which pivots about a fixed point 15 while the arm l6, lixcd to the pendulum acts upon the prongs thcreo 1. The centre of gravity of this member H is located above this axis 15. so that, under the action of its weight, this member tends to fall back-to left or right, but its angular movementis limited by the stop 1'? ar ran ed in the notch c (Figure 5).

Tie arm 16 is made of a good conductor of electricity and is fixed on the, cross-bar T of the suspension device and insulated therefrom by plates and Sleeves of insulating material.

One of the extremities of the coil 4 is connected to the frame-work while the other extremity is connected to the arm 16 by the insulated conductor a.

On the other hand, at the end of the arm 16 there is fixed a small plate 18 of insulating material arranged as shown in the drawing.

The frame of the clocloworl: mechanism consists simply of the standard 19 in which is mounted the shaft of the ratchet. wheel. This standard carries the arm 20 upon which is pivoted the rocking forked member 14 and the arms 21 and 22 in which the axis ll) of the big hand rotates.

A. source of electricity which ma be eunstituted by an ordinary electric battery l is connected on the one hand to the support 1 which latter is electrically! connected, as has been seen, to one of the extremities of the coil l, and on the other hand to the standard 19 constantly in electric connection with the rocking fork 14: which is made of material which is a good conductor of electricity.

The method of opera ion of the clock is as follows:

Starting from the position shown in Fi ure 3., the pendulum begins to oscillate in hie direction of the arrow 1 while the {oi-l; t is thrown over in the direction little before passing to the vertical lillsiliull t'nc conducting end of the arm .3 coznes inlo contact with the prong l inii; ll

and turns it in the direction f Under these conditions, the awl .6, being in engagement with one of t e teeth of the ratchet 7 causes it to rotate as shown in Figure 4.

' When the endulum, continuing its stroke in thc direction i has passed the vertical, the fork falls back in the direction f and assumes the position shown in Figure 5.

The proportions of the parts are chosen such that the rotation of the ratchet 7 pro duccd by the movement of the fork 14 corresponds toan advance slightly greater than one tooth. On the other hand, the position of the-stop 17 is such that the prong B of the forkl moves down and offers no resistance to the-movement-of the pendulumwhich continues its oscillation freely in the direction f Onthe return of thependulum in the direction f,. the insulatingplate 18 carried by 35 the arm 16 acts u'pomthe prong B of the fork 14, as shown in, Figure 6, and obliges the forlrto turn in'lthe direction f' Under these circumstances,.the pawl'6 returns to the rear, but the ratchet wheellremains in place, the nose of the pawl sliding over the back of the tooth; theiriction of said nose not being sufficient to turn the ratchet-wheel backwards.

At the end of the stroke in the direction, 7' the pendulum and the fork 14 resume the position shown inFigure 3 and the operation just described is repeated in the same manner;

It will therefore be seen that, at each os- 1'00 cillat-ion of the pendulum in the direction f,, the ratchet. wheel moves forward by one toothand an electric contact is produced between the conducting endof the arm 16 connected, to one ofthe extremities of the coil and the fork 1-}, which is also a conductor, and isconnected to one of the poles of the source of electricity. It willbo seen that this electric contact closes the circuit comprising the battery P and coil 4. Under these circumstances a force is developed in the direction of the trajectory of the extremity of the pendulum, the direction and amount of said force canbe easily determined so as to keep up the movement of the pendulum. -i i 7 It should be noted that the contact, and consequently thedriving impulse, take place in the neighbourhood of the dead centre, a condition which, as is well known, is very 12o advantageous for the control of the clock.

Breakage of the circuit is very abrupt and the-conducting surfaces which come into contact are kept perfectly clean and are consequently kept in good condition indefinitely. The mechanical operation of the svstemis also very sure and as can be seen, the mechanism only comprises parts which are very simple and of st-rongconstruction hich can be assembled cheaply and easily. ran

It is evident that various modifications in detail could be made in the mechanism described above without departing from the sco e of the invention.

ccording'to a modification a brake is placed upon the shaft of the fork-shaped rocking member, this brake consisting of a spring, which causes slight friction tending to resist the movement of this member when the driving arm acts upon it. The shape of the said member isalso modified in such ainanner that it, is balanced and consequently does not fall over under the action ofits own weight. Instead of a driving arm distinct from the rod of the pendulum there is provided a pin carried by the rod of the endulum and engaging whenthependulum 1s :nearthevertical position. between the prongs of the fork-shaped member. I

The-space comprise between the two prongs of the :fork one: of which carries an insulating piece. is very slightly wider than the diameter 'ofxthe pin. In this manner the result is obtained that the periodical -=closures of the electric circuit, necessary to keep up the oscillating movement of the pendulum. are produced even if the amplitude of the oscillation is very small. under these circumstances the: pendulum is almost completely stopped in consequence of a. shock or movement of the clock; it progressively resumes its normalrunning owing to the successive attractions to which it is subjected. i

The 'present invention also relates to an advantageous form of realization of the mechanism of the clock, the characteristic features of which will be evident from the followingdescription; 7 .1

In1F igures 7 and 12 of theaccompanying drawing the'fork shaped piece is shown at 1". '1 *This piece'is fixed to the shaft 2 pivoted on a fixed frame B. P The fork 1 is shown in detail in Figures "=1O,"-11 and 12. 'Its form is such that its centre of gravity isin the-neighbourhood of its axis so that it remains in' equilibrium y position. Upon the shaft 2 bears a. brake constituted by a leaf spring 3, one of the ends'of which acts upon the shaft with the interposition of a shoe 4. preferably consisting of an alloy of bronze or graphite. The force and tension of the spring 3 are adjusted so that a. slight friction is produced'when the fork 1 is moved.

The fork 1 carries-on the other side an insulating strip 5 and a strip 6. preferably consisting of a. metal which does not oxidize easily; such as silver (Figures 10 and 11).

.The strips form the boundaries of a notch e. inwhicli the pin 7 fixed to the pendulum P can engage, the rod'of the pendulum being'ishownz at 8. Figures 7. 8 and 9. The width of thenoteh e is very slightly greater than the diameter of the pin 7. This pin consists of a metal which is a good conductor of electricity and does not oxidize easily. such as silver. It is fixed on the rod 9* while at the same time being insulated elect ricall v therefrom.

This result can be obtained by fixing the pin on a two part collar 9 and 10 tightly clamped by means of screws 11 and 12 to the rod 8' an insulating sleeve 13 being interposed.

The pin 7" and the fork 1 are interposed in the electric circuit feeding the clock. For example. in the case of a clock whose pendulum carries at its extremity a coil moving in the neighbourhood of a fixed magnet, the electric circuit can be. formed in the following manner. One of the poles of the source of current is connected to the rod 8 of the pendulum by the intermediary o the suspension tremities of the movable coil is connected to the framework in such a manner as to be connected electrically to the pole in question.

The other extremity of the coil is connected by an insulated conductor 14: to the conducting pin- 7. Finally the other pole of the source isconnected to the frame of the mechanism B which should be insulated from the support S of the pendulum. This pole is thereby connected to the fork-shaped piece 1 by means of the pivots and alsoof the brake .4, in the case of which latter every precaution is taken in order to ensure a ,qood electric contact.

The general principle of operation is the same as that described in detail in the prior form of construction. At each stroke in the direction f". and in the neighbourhood of the passage of the pendulum through the vertical line, the electric circuit is closed an c nsequently a driving impulse is given. ut itshould be remarked that when the fork shaped piece 1 is move the friction produced by the spring 3" is opposed to its movement and that this latter does not fall under the action of its own weight.

The result is that the operation of the device is modified in the following manner:

When the pendulum, starting from the position shown in Figure 7 moves in the direction f contact is established as soon as the pin 7 acts upon the conducting edge of the notch a and the fork l. seeFigure 10. This latter is moved in the direction f and contact is continued until the pin leaves the notch. In view of its inertia the fork 1 continues this movement by a slight amount and the electric current is broken. For this to happen it is necessary that the form of the upper parts of the prongs of the fork should besuch that they do not touch the pin 7* while the pendulum con tinues its stroke. The'friction of the spring 3 is sufficient to maintain the fork 1 in position as soon as the pin ceases to act device and one of the' exthe said arm, a awl carried by sai 1,41 mac ing member, adapted to be opened and closed thereby, and means for preventing electric contact between said arm and said rocking member, in one direction of oscillation only.

5. In an electric clock, the combination with a pendulum, an electric coil fixed to said pendulum and a fixed permanent magnet cooperating with said coil, of an arm rigidly fixed to said pendulum, a forked rocking member adapted in operation to be alternately engaged by and disengaged from the said arm, an electric circuit comprising a source of current and said electric coil, a gap in said circuit, between said arm and said rocking member, adapted to be opened and closed thereby, and an insulating piece interposed between said arm and one of the prong-0f said forked rocking member.

6 an electric clock, the combination with a pendulum, an electric coil fixed to said pendulum and a fixed permamcnt magnet co-operating with said coil, of an arm rigidly fixed to said pendulum, a forked rocking member adapted in operation to be alternately engaged by and disengaged from the said arm, means carried by said rocking member for actuating the clock-work mechanism, an electric circuit comprising a source of current and said electric coil, a gap in 80, (said circuit, between said arm and said rocking member, adapted to be opened and closed thereby, and an insulatingpiece interposed between said arm and one of the prongs of said forked rocking member. 7. In: an electric clock, the combination with a pendulum, an electric coil fixed to said pendulum and a fixed permanent mag net co-operating with said coil, of an arm rigidlyjfixed to said pendulum, a forked rocking member adapted in operation to be alternately engaged by and disenga ed from rocking member, a rate et wheel connected to the shaft of the clock-work mechanism, said pawl co-operating with said ratchet wheel, an electric circuit comprising a source of current and said electric coil, a gap in said circuit, between said arm and said rocking member adapted to be opened and closed thereby, and means for preventin electric contact between said arm and sai rocking member during the return stroke of said pawl.

8. In an electric clock, the combination with a pendulum, an electric coil fixed to said pendulum and a fixed permanent magnet co-operating with said coil, of an arm rigidly fixed to said pendulum, a forked rocki ng member adapted in operation to be alternately engaged by and disengaged from the said arm, means carried by said rocking member for actuating the clock-work mechanism, and a brake permanently acting upon said rocking member for arresting its motion after its release by the arm.

9. In an electric clock, the combination with a pendulum, an electric coil fixed to said pendulum and a fixed permanent magnet co-operating with said coil, of an arm rigidly fixed to said pendulum, a forked rocking member adapted, in operation, to be alternately engaged by and disengaged from the said arm, an electric circuit comprising a source of current and said electric coil, a gap in said circuit, between said arm and said rocking member, adapted to be opened and closed thereby, means for preventin electric contact between said arm and sai rocking member, in one direction of oscillation only, and a brake permanently acting upon said rocking member for arresting its motion after its release by the arm.

10. In an electric clock, the combination with a pendulum, an electric coil fixed to said pendulum and a fixed permanent magnet co-operating with said coil, of an arm rigidly fixed to said pendulum, a forked rocking member ada ted, in operation, to be alternately engaged y and disenga ed from the said arm, means carried by sai rocking member for actuating 'the clock-work mechanism, an electric circuit comprising a source of current and said electric coil, and a gap in said circuit, between said arm and said rocking member, adapted to be opened and closed thereby, means for preventing electric contact between said am and said rocking member, in one direction of oscillation only and a brake ermanently acting upon said rocking member for arresting its motion after its release by the arm.

MAURICE PHILIPPE FAVRE-BULLE. 

